DEC’s LAN Bridge 100: The Invention Of The Network Bridge

August 27, 2024 by Maya Posch 13 Comments

DEC’s LAN Bridge 100 was a major milestone in the history of Ethernet which made it a viable option for the ever-growing LANs of yesteryear and today. Its history is also the topic of a recent video by [The Serial Port], in which [Mark] covers the development history of this device. We previously covered the LANBridge 100 Ethernet bridge and what it meant as Ethernet saw itself forced to scale from a shared medium (ether) to a star topology featuring network bridges and switches.

Featured in the video is also an interview with [John Reed], a field service network technician who worked at DEC from 1980 to 1998. He demonstrates what the world was like with early Ethernet, with thicknet coax (10BASE5) requiring a rather enjoyable way to crimp on connectors. Even with the relatively sluggish 10 Mbit of thicknet Ethernet, adding an Ethernet store and forward bridge in between two of these networks required significant amounts of processing power due to the sheer number of packets, but the beefy Motorola 68k CPU was up to the task.

To prevent issues with loops in the network, the spanning tree algorithm was developed and implemented, forming the foundations of the modern-day Ethernet LANs, as demonstrated by the basic LAN Bridge 100 unit that [Mark] fires up and which works fine in a modern-day LAN after its start-up procedure. Even if today’s Ethernet bridges and switches got smarter and more powerful, it all started with that first LAN Bridge.

Continue reading “DEC’s LAN Bridge 100: The Invention Of The Network Bridge” →

Shipwreck Exploration Vessels Fit In Minivan; Stream To Internet

June 2, 2016 by Donald Papp 2 Comments

Having to work away from the convenience of a workshop can be tough. But it’s sometimes unavoidable and it always means planning ahead. When the work area also happens to be 150m under a lake’s surface, it’s much more of a challenge – but it’s both doable and more accessible than you might think. To prove it, this DIY research vessel will be part of the robotic exploration of an underwater shipwreck. It is complete with an Ethernet bridge, long-range wireless communications, remotely operated underwater vehicle (ROV), the ability to hold a position, and more. The best part? It can all be packed up and fit into a minivan. We can’t put it any better than the folks at the OpenROV Forums:

In just over a week (June 6th – 9th), a bunch of people from OpenROV are going to attempt to dive a set of specially modified deep-capable ROVs to a 50m-long shipwreck at a depth of 150m below lake Tahoe. We’ll be using a deployment architecture that we’ve been perfecting over the years that involves a very small boat keeping station over the dive site while the rest of the people on the expedition run the mission from a remote location via long-range broadband radio. Since the mission control site will have an internet connection, we’ll be able to live stream the entire dive over the internet.

The purpose of the design was “to demonstrate that many of the capabilities one might think would require a large research vessel can actually be achieved with off-the-shelf parts that are more portable and much less expensive. […] There’s a lot to discover down there, and the technology readily available these days can allow us to explore it.” This mindset happens to wonderfully complement the kickoff of the Citizen Scientist Challenge portion of the 2016 Hackaday Prize.

For those times when your work can remain on solid ground, one method is to sidestep the entire issue of working away from the workshop by simply making your whole work area mobile like this incredible conversion of a truck trailer to a mobile lab.